SYDNEY — (CNN) Officials are expressing growing confidence that the piece of wreckage found on the shores of a remote Indian Ocean island this week is part of missing Malaysia Airlines Flight 370.

Martin Dolan, the head of the Australian agency coordinating the underwater search for the plane, told CNN on Friday that he is “increasingly confident, but not yet certain” that the debris is from MH370.

Authorities are “highly confident” that the object found Wednesday by people cleaning a beach on the French island of Reunion is from a Boeing 777, Dolan said, and “the only 777 aircraft that we’re aware of in the Indian Ocean that could have led to this part floating is MH370.”

Aviation investigators still have to make a definitive judgment on whether the item, which appears to be a wing component, is from the Malaysian jetliner that disappeared nearly 17 months ago with 239 people aboard.

If it is confirmed, the piece of wreckage would be the first bit of physical evidence recovered from MH370. It could help resolve some questions about the deeply puzzling fate of the aircraft but is likely to leave many others still unanswered.

Here’s where things stand:

THE LATEST

Boeing investigators are confident that the debris discovered on Reunion, which lies roughly 700 kilometers (435 miles) east of Madagascar, is from a 777 aircraft, according to a source close to the investigation.

The source said Boeing investigators are basing their view on photos that have been analyzed and a stenciled number that corresponds to a 777 component. A component number is not the same as a part number, which is generally much longer.

Images of the debris also appear to match schematic drawings for the right wing flaperon from a Boeing 777. A flaperon helps the pilot control the aircraft. It is lightweight and has sealed chambers, making it buoyant.

New debris, which washed ashore Thursday and appears to resemble remnants of a suitcase, is also part of the investigation, Reunion Island police officials confirmed to CNN.

But Australian Deputy Prime Minister Warren Truss said officials were less sure that “the bag has anything to do with MH370” than they are about the plane wreckage.

Teams in Reunion have continued to search the stretch of coast where the debris was found.

THE NEXT STEPS

The plane debris will be transported to France on Friday evening, a spokeswoman for the Paris prosecutor’s office said.

Agnes Thibault-Lecuivre said the piece is expected to arrive in Paris on Saturday and will then be sent to the city of Toulouse, where aviation investigators will analyze it next week.

Malaysia, which is responsible for the overall investigation into MH370’s disappearance, is sending teams of aviation officials to Toulouse and Reunion, the country’s Prime Minister said Thursday.

It’s unclear when the identification process will be completed and its results announced.

“I understand that the photographs that are available are of such detail that it may be possible to make an identification without further physical examination,” Truss said Friday.

THE THEORIES

The photographs have enabled aviation experts around the globe to weigh in on what they think the piece of wreckage might tell investigators — if it is confirmed to be from MH370.

One group of independent observers said Thursday that the damage to the flaperon should give authorities a good indication that the piece came off while the plane was still in the air.

The group, led by American Mobile Satellite Corp. co-founder Mike Exner, points to the small amount of damage to the front of the flaperon and the ragged horizontal tear across the back.

The rear damage could have been caused if the airliner had its flaperon down as it went into the ocean, some members of Exner’s group wrote in a preliminary assessment after looking at photos and videos of the component.

But the lack of damage to the front makes it more likely the plane was in a high-speed, steep, spiral descent and the part fluttered until it broke off, the group said.

But an aircraft component specialist who spoke to CNN disagreed.

The lack of damage to the front section “tells me that the component could still have likely been back in its original position inside the wing itself,” said Michael Kenney, senior vice president of Universal Asset Management, which provides plane components to airlines.

THE INVESTIGATION

Authorities have so far been unable to establish why Flight 370 flew sharply off its route from Kuala Lumpur, Malaysia, to Beijing and disappeared on March 8, 2014.

A preliminary assessment by U.S. intelligence agencies, produced in the wake of the MH370 disaster, suggested it was likely someone in the cockpit deliberately caused the aircraft’s movements before the Malaysian airliner disappeared.

Two U.S. officials briefed on the matter told CNN that the assessment, which was not intended for public release, was prepared months ago and was solely based on available satellite and other evidence.

The U.S. intelligence assessment was largely focused on the multiple course changes the aircraft made after it deviated from its scheduled Kuala Lumpur to Beijing route. Analysts determined that, absent any other evidence, it’s most likely someone in the cockpit deliberately moved the aircraft to specific waypoints, crossing Indonesian territory and eventually toward the south Indian Ocean.

Malaysian investigators haven’t reported finding any evidence that casts suspicion on the pilots.

The airliner’s crew has been the focus of attention since the mysterious disappearance, but no proof has emerged indicating they intended to destroy the plane. Law enforcement and intelligence agencies from numerous countries examined the plane’s manifest of crew and passengers and found no significant information to suggest anyone on board posed an obvious threat.

THE FAMILIES

The discovery of the debris this week is just the latest jolt family members of those on board have had to endure in more than 500 days of uncertainty about the fates of their loved ones.

Many relatives expressed wariness of jumping to conclusions about the origin of the wreckage found on Reunion, pointing to repeated false alarms in the past.
“We do not want to hear guarantees of 99% likelihood from certain authorities,” a group of Chinese families. “We need confirmation of 100% certainty.”

Some family members have said that while they want closure on what happened, confirmation that the object is from MH370 would crush their remaining hopes that their loved ones might still be alive.

“We admit, we still do hope that one day they’ll come back,” said Maira Elizabeth Nari, the 18-year-old daughter of Andrew Nari, the chief steward on the plane. “But if they’re not, then it’s okay. We’ll accept whatever it is, though many of us are in denial.”

THE SEARCH

Confirming that the part is from MH370 would establish “really beyond any doubt” that Flight 370 ended its journey in the Indian Ocean, Truss said Friday.
It would also bolster Australian officials’ confidence that they are searching for the rest of the plane’s wreckage in roughly the right place, he said, as models of ocean currents make it credible that some debris would drift to the region around Reunion.

But the wreckage is unlikely to help with the underwater search for the remains of the plane, which is taking place in a remote part of the southern Indian Ocean, far off the western coast of Australia.

“I don’t think it contributes a great deal to our knowledge of where the aircraft is located,” Truss said, noting the length of time since it entered the water and “the vagaries of the currents.”

Investigators need to find Flight 370’s flight recorders to have any hope of gleaning a better understanding of what happened on board the plane all those months ago.

And relatives want to know what became of their loved ones.

“No matter where the debris is found, we care more about the whereabouts of our family members,” the statement from the Chinese families said.

The-CNN-Wire ™ & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved. (PHOTO: CNN/Réunion 1ère)